Pre-eclampsia/eclampsia is responsible for upwards of 20% of maternal morbidity and mortality in developing countries. We examine the relationship between food intake and symptoms of pre-eclampsia and eclampsia among Indian women aged 15-49 (n=39,657) for the most recent live birth in the five years preceding the National Family Health Survey-3 (2005-06). Daily consumption of milk, vegetables, chicken/meat and weekly pulses/beans consumption are associated with substantially lower risk of pre-eclampsia. Eclampsia risk is higher among those who consumed fruit and chicken/meat occasionally, and lower among those consuming vegetables daily.

Background

Pre-eclampsia and eclampsia pose significant threats to maternal health, particularly in developing countries. In low-and middle-income settings, these two conditions affect approximately 8% of all pregnancies, causing an estimated 15%-20% of maternal morbidity and mortality. Pre­eclampsia is a life threatening complication of pregnancy that typically starts after the 20th week of gestation. Women with pre-eclampsia may present with symptoms such as headache, upper abdominal pain, or visual disturbances and have raised blood pressure, ankle oedema and proteinuria. When pre-eclampsia is left untreated or is severe, giving rise to seizures/convulsions which cannot be attributed to other causes (such as epilepsy), the condition is known as eclampsia. Although several studies have found that micronutrient deficiencies, such as iron, vitamin A, vitamin C, and calcium, contribute to pre-eclampsia risks, few studies have evaluated the potential role of different food types.

Objectives

Existing nutritional evidence is highly variable. Dietary patterns may influence maternal antioxidant levels, mediating the link between pre-eclampsia and oxidative stress, an established risk factor. However, consumption of high-energy diets may increase risk of pre-eclampsia by inducing abnormal lipid metabolism, while consumption of dietary fibre may regulate these metabolic processes, thereby reducing risk. However, studies which have attempted to test these links empirically have not been conducted in high burden countries, nor have they employed appropriate multivariate models. To our knowledge, there has not been any previous large-scale report concerning the dietary risk factors for pre-eclampsia and eclampsia in Indian women. Here, we evaluate potential dietary risk factors of pre-eclampsia and eclampsia, using a large representative sample of Indian mothers in the third National Family Health Survey conducted during 2005-06.

Methodology

Data were taken from the most recent wave of the National Family Health Survey (NFHS-3, 2005–2006), India’s Demographic and Health Surveys. NFHS-3 collected demographic, socioeconomic and health information from a nationally representative probability sample of 124,385 women aged 15–49. The sample is a multistage cluster sample with an overall response rate of 98%. All states of India are represented in the sample (except the small Union Territories), covering more than 99% of the country’s population. The analysis presented here focuses on 39,657 women in the sample who report being married and who have had a live birth in the five years preceding the survey. The survey was conducted using an interviewer-administered questionnaire in the native language of the respondent. To assess the occurrence of pre-eclampsia, mothers were asked if at any time during their last pregnancy they experienced relevant symptoms, including difficulty with vision during daylight, night blindness, convulsions (not from fever), swelling of the legs, body or face, excessive fatigue, or vaginal bleeding. Women who reported difficulty with vision during daylight, swelling of the legs, body, or face, or excessive fatigue were coded as having symptoms of pre-eclampsia, whereas those who reported experiencing convulsions (not from fever) were coded as symptomatic of eclampsia. Data on blood pressure and proteinuria during pregnancy were not available in the NFHS. Dietary intake variables were based on the self-reported frequency of consumption of milk or curd, green leafy vegetables, fruits, pulses and beans, eggs, fish, chicken or meat, categorised into daily, weekly, occasionally, or never. Potential confounders and covariates were selected on the basis of previous knowledge of their association with pre-eclampsia/eclampsia. We used multiple logistic regression to estimate the association between variation in dietary intake and pre-eclampsia and eclampsia risk after adjusting for maternal factors, biological and lifestyle factors and socio-demographic characteristics of the mothers. Models were adjusted for sampling weights (IIPS & Macro International 2007). All analyses were conducted using the SPSS statistical software package Version 19.

Results

Overall 55.6% of mothers reported pre-eclampsia symptoms, and 10.3% reported eclampsia. Table 1 reports the results of our statistical models. After adjusting for maternal, biological, and chronic disease risk factors, as well as socio-demographic characteristics, we found that the risk of pre-eclampsia was significantly lower among women who consumed milk daily (OR:0.88;95%CI:0.81-0.96), green leafy vegetables daily/weekly (OR: 0.69 to 0.76), pulses or beans at least weekly/occasionally (ORs ranges from 0.84 to 0.92), fruits daily (OR:0.92), eggs weekly/occasionally, consumes fish (OR:0.90) or chicken/meat daily or occasionally, with added reference to those who never consumed them. However, a greater risk of pre-eclampsia was found among women consuming fruits weekly/occasionally (OR:1.11), eggs daily (OR:1.23) and fish weekly (OR:1.22). The risk of eclampsia was lower among those consuming green leafy vegetables (ORs ranges from 0.74 to 0.79), consuming fish weekly or occasionally (ORs ranges from 0.44 to 0.62), eggs weekly or occasionally (Ors ranges from 0.61 to 0.76), but was higher among those who consumed fruits (ORs ranges from 1.18 to 1.44), chicken/meat occasionally (OR:1.28;95%CI:1.11-1.48) with reference to those who never consumed them.

Conclusion

Our study provides empirical evidence of an association between the frequency of intake of specific food items and prevalence of pre-eclampsia/eclampsia in a large nationally representative sample of Indian women. Findings suggest that variation in the frequency of consumption of specific foods has a substantial effect on the occurrence of symptoms suggestive of pre-eclampsia/eclampsia in this population. The strengths of our study include the large nationally representative study sample and the population-level focus on the predictors of pre-eclampsia and eclampsia. However, due to the general challenges of measuring hypertensive disorders in population-based studies, the information of the symptoms of pre-eclampsia and eclampsia presented here is based on self-reports and should therefore be interpreted with care. Although we adjusted for several confounding variables, we cannot exclude the possibility of residual confounding. In these analyses, the cross-sectional design precludes causal inferences and we were limited to the questions used to elicit lifestyle and dietary information. Few population level studies exist which assess the dietary determinants of pre-eclampsia and eclampsia. This study is important because few others have reported pre-eclampsia/eclampsia prevalence rates based on population-level data. Our study implicates that modifiable risk factors for pre-eclampsia/eclampsia exists and thus there is a need for replication of findings given that the dietary patterns are modifiable. Our study findings may serve as an important call for health care providers to heighten their awareness of the increased population-level risk for pre-eclampsia and eclampsia disease originating in pregnancy. With the target of the Millennium Development Goals in sight, pre-eclampsia/eclampsia should be identified as one of the priority areas in reducing maternal mortality in India. However, further research involving the use of a more comprehensive dietary measure, pre-pregnancy assessment of all the risk factors and ascertainment of dietary intake prior to the development of pre-eclampsia and eclampsia and accuracy of reporting of the symptoms of pre-eclampsia and eclampsia are needed in a developing country setting.